Going To Buy A Lathe... Thoughts, Input Solicited By Inexperienced Dufus

[JimDawson]

I would just use whatever size is in there now, proabaly metric. I normally use grade 8 US or 12.9 Metric all-thread for jack screws. A 5/8 or 1/2 inch thick, 4x4 steel plate under them works well. I normally put a divot in the plate with a drill bit that is a little larger than the jack screw just to keep it from walking around.

 

[markamerica]

I would just use whatever size is in there now, proabaly metric. I normally use grade 8 US or 12.9 Metric all-thread for jack screws. A 5/8 or 1/2 inch thick, 4x4 steel plate under them works well. I normally put a divot in the plate with a drill bit that is a little larger than the jack screw just to keep it from walking around.

Yeah, what I was thinking about was some pipe flange studs, something in the range of 1"-1-1/4". Sometimes you can find lots of them for not too much...relatively.

 

[markamerica]

I would just use whatever size is in there now, proabaly metric. I normally use grade 8 US or 12.9 Metric all-thread for jack screws. A 5/8 or 1/2 inch thick, 4x4 steel plate under them works well. I normally put a divot in the plate with a drill bit that is a little larger than the jack screw just to keep it from walking around.

The other thing I was thinking about that's really advantageous with my removable front outriggers: When not in use, I could use them elsewhere, for instance if I wanted a similar arrangement for a Bridgeport/clone to what you have. Once it's in place, I could again crank down the leveling screws, pull the outriggers, and boom. Done. In a sense, with six removable outriggers I could use for any machine in the shop, I make it all movable and minimize the number of casters I'm buying. Same CG-lowering underslung construction across the board, and same basic approach to all the machines. Make sense? I think I like it, conceptually.

 

[markamerica]

I would just use whatever size is in there now, proabaly metric. I normally use grade 8 US or 12.9 Metric all-thread for jack screws. A 5/8 or 1/2 inch thick, 4x4 steel plate under them works well. I normally put a divot in the plate with a drill bit that is a little larger than the jack screw just to keep it from walking around.

Jim, One other quick question: Do you think 1/4" wall thickness will be sufficient on my square tube? I think it would be, only because the 3 pedestals will be supported all around their perimeters, and the long lengths of the main beams spanning between the pedestals will really only provide tie-together for the whole structure, aka alignment. I could just as easily build three independent dollies, but thought having it all tied together in the manner above would make it all a bit simpler when setting the lathe onto it.

 

[JimDawson]

Given the way it's supported, I think 1/4 wall would be fine. You're not going to have that much weight at any single point.

 

[markamerica]

Given the way it's supported, I think 1/4 wall would be fine. You're not going to have that much weight at any single point.

Jim,

Good, that's what I was thinking. I looked at some of the other rolling items I have and how they're constructed, how much weight they bear, and decided it should be fine, but then I thought: "Hmm, but I've never done one on this scale..." and figured a second (or third or twentieth) opinion might be a good idea.

Thanks again!

Mark

 

[bfd]

lets look at some intangebles: older lathes mostly have slower speed limits, the thread lead screw is also the carriage feed rod AND if equipped the crossfeed rod. higher wear on one item. as far as metric threads goes you caN add tHe 127 tooth gear which can be quite large mayh not fit in the back gear cover, there are other choices of gearing set ups avail. but some metric set ups require you to stop the lathe and back out the tool bit reverse the lathe and bring it back to the start and repeat the process over you can never release the half nut until threads are completed. we have some newer leblond lathes at work that do tHat and my frejoth Chinese lathe did the same thing. my existing enco threacs metric and standard normally. the new Chinese junk stuff has 3 rods on the front thread, long and cross feed and remote on off switch. I too wish for a taper attachment but I have owned a lathe for some 40 years and have done without. bore size is nice but 2" is big and maybe not required. find what will do and move up whenabsolutly required. my dimes worth bill

 

[bfd]

beg borrow or steal a pallet jack build a cribbing frame up from underneath the ways and use the tailstock and or carriage to balance the load. remove the chippan. worked for me. ps don't steal a pallet jack just kidding here. do you have an electrician friend. with his help you can rewire your lathe controls. I changed a 3 phase 7.5 hp. lathe to a single phase 7.5 hp. lathe works great except you give up instant reverse, you have to wait for the cent switch to reset before you can reverse rotation. the old ways were cast iron good cast iron but most likely not induction hardened this process gives you a lot more resistance to wear. your lathe looks similar to mine and appears to be hardened so it looks good. your thinking about way wear changing the od of the oart being machined is good but it should be a minimal radius change. boy am I long winded bill

 

[markamerica]

Bill, thanks for all the info! You're not long-winded. Look at one of my posts... Now that babble-fest is long-winded. Judging by the amperage on the data plate for this motor, I'd guess it's around 15 HP. When I go looking at specs on 3 phase motors, one with a rating of 38-40amps at 240v is usually a 15 horse.

Does this lathe even do instant reverse? I don't know, newbie that I am. If so, will it work with a rotary phase converter? I read somewhere you couldn't do that with a static phase converter, but don't know about rotary.

I'll be getting a rotary converter soon. I figure I'll need one that will start a 15hp at most.

Anyway, I'd like to start figuring out that stuff a little. It will be a bit before it runs. Who knows what I'll end up needing? I expect probably a transformer for the controls, relays, blah blah blah. Basically, all new electrics, maybe including motor.

Thanks!

Mark

 

[JimDawson]

Does this lathe even do instant reverse? I don't know, newbie that I am. If so, will it work with a rotary phase converter? I read somewhere you couldn't do that with a static phase converter, but don't know about rotary.

That's a lot of rotating mass to instant reverse, but the lathe will probably do it. There is a good chance that reverse on that lathe is accomplished by a mechanical clutch rather than reversing the motor. Pretty sure the For/Nut/Rev is mechanical on that lathe.

You can instant reverse a 3 phase motor with a RPC and you can do it with a static phase converter also, at least I've been doing it for the last 20 years on my 3hp lathe. There are very few machining operations where you need instant reverse, power tapping for instance. But I normally plan the operation so I don't have to.